Delayed arming circuit for mines



Feb. 22, 1955 BENNETT ET AL 2,702,507

DELAYED ARMING CIRCUIT FOR MINES Filed Nov. 20, 1942 V 2 SheetsSheet 1 an 7 m;

46 FIRING 2| 22 47 MECHANISM 25 2e 2 so I 23 3| 0 l6 7 I8 54 2: W 42 44 43 $4 $3 la s2 grwwtow R, 0. BENNETT E. L. DEETER Feb. 22, 1955 R.D.BENNETT AL Filed Nov. 20, 1942 2 Sheets-Sheet 2 l 4 22 ,29 1 25 2 2 I. 27 gin 0mm R. o. BENNETT E. L. DEETER DELAYED G CIRCUIT FOR MINES Ralph 1). Bennett, United States-Navy, and Everett L. eeter, Washington, D. C.

Application November 20, 1942, Serial No. 466,288

12 Claims. (Cl. 10216) (Granted under Title 35, U. S. Code (1952), see. 266) This invention relates to an arming device for a mine in which the mine is armed when a predetermined period of time has elapsed after the mine has been planted. More specifically, the invention relates to an electrically fired mine in which an arming circuit is made effective in predetermined time delayed relation with respect to the planting of the mine, and in which the extent of the delay is controlled by the decrease in the potential of a battery arranged within the mine as a discharge current is drawn therefrom by a predetermined load connected thereto as the mine is planted.

Various devices have heretofore been employed for delaying the arming of a marine mine, such devices comprising in general a clockwork mechanism or an electric motor arranged to operate certain circuit closing devices when the operating mechanism has completed a cycle of operations, various devices including pistons, dash pots and the like, and devices having a soluble element adapted to be dissolved or softened sufficiently by the water within which the mine is immersed to operate a circuit closing device associated therewith in time delayed relation with respect to the planting of the mine. While such devices are adapted to effect a delay in the arming of a marine mine, there are instances in which these devices have failed to operate satisfactorily in service for the reason that the cycle of operations of the arming delay mechanism may not be completed as the result of mechanical failure of the mechanism or the failure of the soluble element to dissolve.

In the arrangement of the present invention an electrical load is connected to the terminals of a battery at the time of planting of the mine and remains continuously connected thereto until the mine explodes, thereby discharging the battery at a predetermined rate and thereafter maintaining the battery completely discharged. When the voltage of the battery has decreased to a predetermined value a relay operatively connected thereto is caused to release and close a pair of contacts thereby completing an arming circuit to the firing control mechanism. The arming circuit is prevented from being closed prior to the launching of the mine by a pair of contacts maintained in the open or disengaged position by a latch arrangement controlled by the aforesaid relay. The latch arrangement also controls the closure of another pair of contacts whereby a resistive load is applied to the battery as the relay operates. The resistive load may be of any suitable type, but we prefer to employ for this purpose the metallic filament of an electric lamp possessing a steep volt-time characteristic whereby the resistance of the discharge circuit of the battery decreases rapidly in proportion to a decrease in the voltage applied thereto and thus the voltage of the battery is lowered at a relatively rapid rate during the latter part of the discharge cycle thereof and the time of the release of the relay and the closure of the arming circuit thereby may be predetermined.

One of the objects of the present invention is to provide new and improved means for delaying the closure of an arming circuit for a marine mine in which the delay is controlled by the rate of discharge of a battery.

Another of the objects is to provide a new and improved electro-responsive device adapted to switch on a discharge load circuit to the battery as the device operates and close an arming circuit when the battery has been discharged to a predetermined potential.

Another of the objects is to provide a time delay arming device for a mine which will be economical to manufac 2,762,507 Patented Feb. 22, 1955 ture, reliable in operation and which possesses all of the qualities of simplicity of construction and reliability in operation.

Still other objects, advantages and improvements will become apparent from the following description taken in connection with the accompanying drawings of which:

Fig. 1 shows in diagrammatic form a complete system in accordance with a preferred embodiment of the invention;

Fig. 2 is an enlarged view partially broken away of the relay and locking mechanism showing a fuse element operatively connected thereto;

Fig. 3 is a sectional view taken centrally through the relay and locking mechanism of Fig. 1; and F Fig. 4 is a sectional view taken along the line 44 of Referring now to the drawings on which like numerals of reference are employed to designate like parts throughout the several views and more particularly to Fig. 1 thereof on which is shown in diagrammatic form a complete system in accordance with the preferred embodiment of the invention, the letter R is employed to designate an electro-responsive relay having contact elements adapted to be operated in predetermined sequential order as the relay operates. One terminal of the relay is connected by way of the conductor 10 to the positive terminal of a battery B1, which may be of any suitable type having sufficient capacity to operate the relay R and maintain the relay operated for a predetermined period of time after an additional load has been applied thereto, the conductor 10 also extending. to the electrical load L and to one end of the fuse 20. The load L, as heretofore stated, comprises a resistive element having a temperature coefiicient arranged to decrease the resistance of the element as the current flowing therethrough is decreased whereby the voltage of the battery decreases at a relatively rapid rate as the condition of the battery becomes more nearly discharged and thus the extent of the time delay before the arming circuit is closed may be predetermined with a relatively high degree of accuracy by the appropriate selection of the resistance L.

The other terminal of the Winding of relay R is connected by way of conductor 11 to the contacts of a switch concurrently into engagement with their respective con-' tacts as the restraint is' removed from the switch S3 by the armature of relay R as the relay operates. Relay R, it will be noted, is provided with a latch member arranged within the path of travel of the end of the contact spring of switch S3 whereby the normally closed switches S3 and S4 are latched in an open position until relay R operates.

Relay R is prevented from operating prematurely as the result of a violent shock or blow which the mine may receive during the handling, transportation and planting of the mine, by the lock member 16 pivotally mounted within a recessed portion 17 of the spool head 18 as by the pin 19 and maintained within the path of travel of the armature of the relay by the fuse 20 secured thereto in any suitable manner as by the screw 21 and washer 22, the other end of the fuse being clamped to the block 23 as by the screw 24 and block 25. A spring 26 is arranged about the pin 19 on opposite sides of the lock 16 and provided with extending ends 27 in engagement with the spool head 18 whereby the lock is urged toward the position shown in dashed outline on Fig. 3 in engagement with an inclined surface 28 of the spool head 18 but restrained from movement from the position shown in solid outline on Fig. 3 by the fuse 20. With the fuse 20 in the assembled position, the lock member is maintained in the locked position with the lock member in engagement with the portion 29 within the spool head 18. There is also arranged against the screw 21 a short length of flexible conductor 30 secured at one end thereof to a by an electrical circuit is established to the fuse 20 through the conductors and 11. The terminal 31 is secured to the spool head 18in any suitable manner as by the screw 32.

As the fuse 20 operates in response to a fiow of sufficient current therethrough, the restraint is removed from the lock 16 thereby causing the lock to beactuated by the spring 26 to the dashed position shown on Fig. 3 with the portion 33 thereof moved out of the path of travel of the relay armature and thus the restraint is removed from the armature of the relay and the relay is free to operate in response to the surge of current through the winding thereof as the shunt across the winding is removed by the operation of the fuse.

The fuse block 23 may be supported in any suitable manner. such, for example, as bythe bracket 34 secured thereto and to the spool head 18 as by the screws 35 and 36 respectively. The relay armature has secured thereto a latch 37 in any suitable manner as by the rivets 38 adapted to'engage the end 39 of suitable insulating material of the contact spring 41 and maintain the contact spring disengaged from the contact screw 42 until relay R operates. With the contact spring 41 in the latched position, a contact spring 43 is maintained disengaged from the. contact spring '44 by a spacing member 45 of insulatingmaterial suitable for the purpose such, for example, as rubber, fiber, Bakelite or the like. The relay is. also provided with a pair of normally closed contact springs 46 and 47 adapted to be disengaged from each other as the relay operates and move into engagement with each other as the relay releases.

The contact spring 41 is connected as by the conductor 48 to the negative terminal of battery E2, the positive terminal of battery B2 being connected by a conductor49 to'one terminal of an electro-responsive detonating device 51, the other terminal of the detonating device being connected to the firing mechanism as by the conductor 52 from whence the circuit is continued by wayof'conductor 53, contact spring 47, contact spring 46 and conductor 54' to the adjustable contact screw 42.

Switch S1, itwill be noted, is maintained in the open position by a safety pin 55 adapted to be withdrawn from a support 56-by an arming wire 57 connected thereto as the mine is launched.

' The operation of the system will now be described. Let 7 it be assumed,- by way ofexample, that the switches S3 and S4 are latched in theopen position by the armature of} relay R, and thatthefuse wire 20 has been connected in the assembled position whereby the armature of relay R is prevented from moving toward the operated position by the lock member- 16 until the fuse operates. As the pin-55 is withdrawn from the support 56, the switch S1 moves to' closed position thereby closing a circuit from positive terminal of battery B1 by way of conductor 10, fuse- 20' in parallel with the winding of relay R, from whence the circuit is continued byway of conductor 11, contacts of switch S1 and conductor 12 to the negative terminal'of battery B1. As the" fuse 20 operates in response to. the fiow of current through the aforesaid. circuit, the lock member 16 is vrn ovedby the spring 26 to the position shown in dashed outline on Fig. 3 with, the end 33 thereof out of the path of travel of the armature of relay R. The operation of the fuse 20 also removes a short circuit from the winding of relay R, whereby the winding of the electromagnet of relay R is energizedby current from battery B1 as the fuse operates.

As the armature of relay R' movesaway from the released position thereof, contact spring 46 of switch S2 is disengaged from contact spring 47 and, remains disengageduntil relay R releases. As the armature of relay R continues to move toward the operated position thereof the latchrnember 37 is disengaged from the end 39 of the spring 41 thereby causing switches S3'and'S4 to operate. As contact spring 41 of switch 53 moves into engagement with contact 42, negative potential from battery B2 is applied by way of conductors 48 and 54 to-the contact spring 46 ofrelayR but without effect at this time for the reason that contact spring 46 isdisengaged from the contact spring 47. prior to the engagement of contactscrew 42 by the contact spring 41 of switch S3.

As contact spring 43 of switch S4 moves into engagement with contact spring 44 a circuit is' closed'from positive terminal of battery B1 by way of conductor 10,

resistive loadzL, conductor 13;contact springs 43 and 44 of switch S4 and conductor 12 to the negative terminal of battery" B1 thereby closing a discharge circuit from battery B1 through the load L and causing the battery B1 to be discharged sufficiently to release relay R when a predetermined period of time has elapsed and thereafter to continue to discharge the battery until the battery is completely discharged. As heretofore stated, the resistive load L is adapted to decrease the resistance of the load as the voltage of the battery decreases whereby the battery is discharged at a relatively rapid rate when the potential of the battery has been decreased from the initial battery potential by a substantial amount. When a predetermined period of time has elapsed the voltage of battery B1 has decreased sufficiently to cause relay R to release and at the contact springs 46 and 47 thereof close a circuit from negative terminal of battery B2 by way of conductor 48, contact spring 41, contact screw 42 of switch S3, conductor 54, contact springs 46 and 47 of switch S2 and thence by way of conductor 53 to the firing device thereby closing an arming circuit to the firing mechanism and causing the mine to be armed.

As the firing mechanism operates in response to the approach or passage of a vessel within the vicinity of the mine a circuit is closed from the positive terminal of battery B2 byway of conductor 49, detonator 51, conductor 52 and firingcontacts of the firing mechanism, conductor 53, contact springs 47 and 46 of switch S2, conductor 54, contacts 42' and 41 of switch S3 and thence by way of conductor 48 to the negative terminal of battery B2 thereby causing the detonating device 51 to'operate and fire themine.

Briefly stated in summary, the present invention provides new and improved means for delaying the closure of an arming circuit for a marine mine in which an elec trical relay is connected to the terminals of a battery in response to the removal of an arming pin as the mine is planted and in which a resistive load is connected to' the battery as the relay operates thereby causing the battery to discharge and release the relay within a predetermined period of time after the arming pin has been removed,

' the release of the relay causing the arming circuit to be rendered etfective. Whereas in the preferred embodiment of the invention illustrated on the drawings the resistive load is applied to the battery by the closure of a pair of contacts controlled by the aforesaid relay, it will be noted that, if desired, the resistive load may be connected directly across the winding'of the relay and the pair of relay controlled contacts for connecting the load to the battery may be omitted. Moreover, the specific structure disclosed for preventing the operation of the relay until the firing pin has been withdrawn is to be regarded as illustrative rather than limitative'as various other features of construction and instrumentalities may be employed for preventing the premature operation of the relay as the result ofa violent shock or impulse received until the arming pin has been withdrawn. 7

While the invention has been described with particularity as to one preferred embodiment of a combination of mechanisms and, of each of the various elements of.

the combination, it is to be understood that this has been done for purposes of disclosure and that various changesand substitutions may be readily apparent to those skilled in the art, after understanding the inventionherein disclosed, and that. the terms employed in the claims are, therefore, to be considered as words of description rather than of limitation, Y

The. invention herein disclosed and claimed may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment'of any royalties thereon or therefor.

Whatv is claimed as new and desired to be secured by Letters Patent of the United States is:

1'. Arming mechanism for a marine mine comprising, in combination, a battery, an electrical relay, means for causing said relay to be operated by said battery, a resistive load adapted to discharge the battery, means controlled by said relay forconnecting said resistive load to,

the batteryas the relay operates,-an initially open arming circuitadapted. toarm the mine when the circuit is closed, and means. controlled'by said relay for closingsaid arming circuit when the battery has been discharged sufii opened when the relay is operated, means for operatively connecting the winding of the relay to said source of electrical energy thereby to operate the relay, two sets of normally closed contacts initially latched open and adapted to be moved synchronously to closed positions, a relay armature having a latch member adapted releasably to lock both of said .sets of contacts open until the relay operates, a resistive device adapted to be connected to the source of electrical energy by one of said sets of contacts as the sets of contacts are unlocked by said latch member, an initially open arming circuit adapted to be closed in part as the other of said sets of contacts is closed in response to the operation of said relay armature, and means including an electrical circuit connection between the other of said sets of contacts and said normally closed contacts for closing said arming circuit when the potential of said source of electrical energy has been reduced by the resistive device sufficiently to cause the relay to release.

3. In a system for arming a mine in predetermined time delay relation with respect to the planting of the mine, a battery arranged within the mine, an electrical relay having a pair of normally closed contacts, means for switching the relay into operative connection with said battery as the mine is launched, two sets of normally closed contacts, a relay armature having a latch member adapted to maintain both of said sets of contacts initially latched open until the relay operates, means including a fusible device controlled by said switching means for preventing the operation of the relay armature until the relay has been switched into operative connection with the battery, a resistive device operatively connected to one of said sets of contacts and adapted to be connected to the battery as the contacts are unlatched, and an initially open arming circuit including the other of said sets of contacts adapted to be closed in part as the contacts are unlatched and rendered efiective by said normally closed contacts when the battery has been discharged by said resistive device sufiiciently to cause the relay to release.

4. In a device of the character disclosed for delaying the arming of a marine mine, a pair of normally closed contacts, a second pair of normally closed contacts in series connection with the first named contacts, an electro responsive device having means adapted to maintain the second pair of contacts initially latched open until the first named contacts are disengaged, a source of electrical energy, means for causing the electro-responsive device to be operated by said source of electrical energy as the mine is planted thereby to disengage the first named contacts and cause the second pair of contacts to be unlatched and closed after the first named contacts are disengaged, means including a resistive element controlled by the electro-responsivc device and adapted to reduce the voltage of said source of electrical energy continuously, and an initially open arming circuit adapted to be closed by said second pair of contacts and said first named contacts when the electro-responsive device releases in response to a predetermined decrease in the potential of said source of electrical energy.

5. In a device of the character disclosed for arming a mine when a predetermined period of time has elapsed after the mine is planted Within a body of water, an electrical relay having a fusible element in parallel with the relay winding, a battery, means for connecting the battery with the winding of said relay and fusible element in parallel, an armature for said relay, means controlled by said fusible element for locking the armature in an unoperated position until the fusible element operates, two pairs of normally closed contact elements adapted to be moved synchronously from initially latched open positions to closed positions, means including a device on said armature for latching said pairs of contact elements disengaged until the relay operates, a resistive load adapted to be continuously connected to the battery by one of said pairs of contacts as the contacts are unlatched, a control circuit operatively connected to the other of said pairs of contacts and having a second battery therein, a firing mechanism included Within said control circuit, and means on said relay for rendering said control circuit effective as the relay releases in response to a predetermined decrease in the voltage of said first named battery.

6. Arming mechanism for a marine mine comprising, in combination, a source of electrical energy having an initial potential and a relatively constant voltage char'-- acteristic under load for a predetermined period of time, a resistive load, means for connecting the resistive load to said source of electrical energy, an initially open arming circuit adapted to arm the mine when the circuit is closed, and electro-responsive means initially operated from said source of electrical energy and thereafter maintained operatively connected thereto, and including means adapted to close said arming circuit when the potential of the source of electrical energy has decreased from said initial potential by a predetermined amount.

7. Arming mechanism for a marine mine comprising, in combination, a battery, a resistive load having a steep volt-time characteristic, means for operatively connecting said resistive load to the battery as the mine is planted thereby to reduce the potential of the battery from an initial potential to a release potential when a predetermined period of time has elapsed after the load has been connected to the battery, an initially open arming circuit, and an electro-responsive device operatively connected to said battery and including means adapted to close said arming circuit when the potential of the battery reaches said release potential.

8. Arming mechanism for a mine comprising, in combination, a battery, means for discharging said battery at a predetermined rate, an initially open arming circuit, an electro-responsive device controlled by said battery, and means on said electro-responsive device and adapted to close said arming circuit when the battery has been discharged sufliciently to reduce the voltage of the battery to a predetermined value.

9. In a submarine mine, the combination of a mine firing mechanism, a firing circuit adapted to be closed by said firing mechanism, an electro-responsive device having means for continuously interrupting said firing circuit until the device operates, a pair of normally closed contact elements on said electro-responsive device in series connection with said firing circuit adapted to be opened and render the firing circuit ineffective for a predetermined period of time after said circuit interrupting means has closed in response to the operation or" the electro-responsive device, a battery adapted to operate said electro-responsive device, means for operatively connecting the electro-responsive device to said battery, and means controlled by the electro-responsive device for causing the electrical energy within the battery to be expended at a predetermined rate, said electroresponsive device being adapted to close said pair of contact elements and render the firing circuit effective when a predetermined fractional part of the energy of said battery has been expended.

l0. Arming mechanism of the character disclosed comprising a source of initial electrical potential having a relatively constant voltage characteristic under load for a predetermined period of time, an initially open arming circuit, means operatively connected to said source and responsive to said initial potential for closing in part said circuit, means for gradually reducing said potential while said arming circuit is closed in part, and means responsive to a predetermined decrease in said potential for additionally closing said arming circuit.

11. In a system for arming a mine in a predetermined time delayed relationship with respect to the planting thereof, a source of initial electrical potential having a relatively constant voltage characteristic under load for a predetermined period of time and being capable of more complete discharge thereafter, an initially open arming circuit in said mine, latch type relay switch means having first, second and third switches and responsive to application of current from said energy source to partially close said arming circuit through the first switch thereof, a discharge circuit for said electrical source, including the second switch of said switch means, load means in said discharge circuit and controlled by said second switch for gradually reducing said potential while the arming circuit is closed in part, said relay means being responsive to a predetermined decrease in potential for additionally closing the arming circuit through the third switch of the relay switch means While maintaining said first and second switches closed.

12. A mine arming system adapted for operation in a predetermined time delayed relationship with respect to the planting thereof and rendered operative after launching by a self-contained electrical energy source therein, said energy source inherently possessing an initial eleczaosgau'r Referencesreited; inthefile ofithispatent I UNITED STATES PATENTS Heap-ct al'. July 2 2-, 1919 Maxim Iunell, 1921 Dufi-le Apr.. 22,1924 Lea Sept. 1, 192-5. Rypinski Sept. 4,193.4: 

